A completely random split zone test with nitrogen application level as main plots and nitrogen-fertilizer postponing application ratio as sub-plots was designed to clarify the scientific production mode for reducing fertilizer application and increasing efficiency of spring maize in the dryland of Loess Plateau. Three nitrogen application levels were 225 kg/hm²(N1)，275 kg/hm²(N2)and 325 kg/hm²(N3)；sub-plot was nitrogen-fertilizer postponing application ratio，based on base application of 20% nitrogen-fertilizer before sowing and topdressing of 40% nitrogen-fertilizer at the big bell mouth stage，four types of nitrogen-fertilizer postponing application ratio were set up，including M1:traditional nitrogen application，i.e. 40% nitrogen-fertilizer applied at jointing stage；M2:10% of nitrogen postponing applied，i.e. 30% nitrogen-fertilizer applied at jointing stage and 10% at 10 days after flowering stage；M3:20% of nitrogen postponing applied，i.e. 20% nitrogen-fertilizer applied at jointing stage and 20% at 10 days after flowering stage；M4:30% of nitrogen postponing applied，i.e. 10% nitrogen-fertilizer applied at jointing stage and 30% at 10 days after flowering stage. The nitrate reductase(NR)activity in leaves at different growth stages of spring maize，the changes of nitrogen contents of stems and leaves at anthesis and maturity stages，nitrogen transport characteristics after anthesis and grain yield were determined. Results showed that the treatment of M4 significantly increased the activity of NR after jointing in maize leaves，under the same nitrogen fertilizer management mode，medium nitrogen(N2)increased the activity of NR at filling stage and after filling stage of maize leaves，while high nitrogen(N3)inhibited the activity of NR. Nitrogen-fertilizer postponing application increased the nitrogen content of maize stems and leaves at anthesis and maturity stages，nitrogen content of maize leaves in N3 with nitrogen-fertilizer postponing application treatments were 10.1%，14.7% and 23.5% higher than that of M1，respectively. At the same nitrogen level，the more ratio of nitrogen-fertilizer postponing application，the more nitrogen translocation amount，translocation rate and the contribution rate of nitrogen to grain of spring maize stems，while the treatment of M4 significantly increased the contribution rate of leaves to grains at the N2 level. There was no significant difference in grain yield between N2 and N3 treatments in M4. However，the net profit of N2 treatment was significantly higher than that of N3 treatment. Nitrogen application of 275 kg/hm² and 30% nitrogen fertilizer(27.5 kg/hm² N fertilizer was topdressing at the joining stage + 82.5 kg/hm² at 10 days after flowering)was beneficial to the increase of maize yield and farmers’ income.